I could use some PIL graphics assistance... The clouds in the app are beautiful but when I tried to port them to PIL they look ugly. :-( Would it be possible for someone to make the PIL image-based clouds look as beautiful as in the app?

PIL coordinate system is also flipped in y, so you need to use image height minus y.

Scene allowed you to draw outside of the frame, PIL does not. So you need to add 60/15 respectively so the cords are Zero based. Image size should be 200 wide (5th cloud starts at 80, and is 100 wide), and 140 tall (0 to 30 random height, plus 10 for shadow offset).
Then top would be h-i[1], bottom would be h-i[1]-i[2], and you would subtract 10 for both to shift gray cloud down.